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Oldsmobile Cutlass Supreme SX


HomeMessage BoardGeneral Cutlass SX455 Q&AMessages
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General Cutlass SX455 Q&A

Real SX?
Author Last Post
Hi Paul, I have a 1970 cutlass supreme sx convertible with a w32 package. You can see more info on the members directory. It has all matching #'s except for the carburetor, which I just paid big bucks for a period correct 7040257. I have been replacing and restoring parts of it for the last couple years. I have a partial build sheet, protecto plate, copy of the window sticker and much more. Thank you for your interest, jim
Hi Jim;

Tell me more about what you have. Thanks, Paul
Paul, if you are looking for a real sx I may be able to help you. I have a1970 sx convertible that I may sell. I need to down size my cars and that would be the first to go.

Here is a link to the Vehicle History report I pulled on the SX back when I was considering it. Not much to go on. It was titled and registered in Arizona on 2.24.10. That was likely the Barret Jackson sale. Then again in Florida in 2011 and then again in Ohio on 4.28.16. Likely JK Gallery as they hail from Ohio. Maybe they bought it at auction or an owner in Ohio is selling it on consignment, who probably bought it in Fort Lauderdale, FL at the auction.

Since it was built in Lansing, there probably is no Build Sheet and there does not seem be a sales receipt in the documentation available to verify its authenticity. And of course the documentation that is available does not appear to match the VIN on this vehicle.

I was looking at this car as well. I did some research and there have been quite of few exchanges since 2010. The Proteco-O-Plate they offered up as some sort of authenticity did not match the VIN on the car. Proteco-O-Plates don't mean much anyway. But that turned me off to visit and check all the numbers. I believe it was sold again at auction on April 1, 2016, Auctions America Lot 169 for $34,100. Pretty sure this is the same car. JK Gallery even used the same description given on the Auction website. There are others photos there as well including some documentation. That does not seem to match the car.

It may very well be a true SX. I just did not like the sorted history and JK has been trying to sell this for almost a year.

I am not an expert like the others guys on this site. Hope this helps. Brian
Gary, the trans code for a '71 SX is "OD". Can you tell me correct engine code (TA, TN, etc.)?

Thank you.
Thanks for the insight on eBay history and transmission.

I e-mailed and asked about the engine and transmission. They said the engine was original and the transmission was not - not sure if this is kind of liberal interpretation of "numbers matching" assertion? Assume is has some negative impact on the value vs. if the transmission was original matching.

This is the Barrett Jackson auction record from 2010

Should I be concerned about the 35K miles added since 2010 - eBay description said it was driven "sparingly" yet >5K per year average seems like more regular driving? Is 20 years and 50K miles since restoration potentially an issue particularly since they don't know who did the restoration?

Thanks again for any thoughts/insights!
This car has been on eBay for several months--which doesn't mean it's a bad car or not real. The original price was $43900 and was recently reduced to $41800. As far as I know it has never been in an auction format--only as a classified ad.

The earlier comments that several people have made are all good advice regarding the car. I did notice this in their description "Transmission: TH400 erra correct pre 1970"
which would indicate the transmission has been changed. There is a tag on the passenger side of the transmission case visible under the car and it should be an OD code transmission. The partial vin is stamped on the drivers side and is hard to see to photograph.

I would doubt that anyone was faking SX cars 20 years ago when this was restored and the matching numbers engine would go a long way to making me believe that its an original SX

Yeah, the COWL tag won't confirm it's an SX. You'd really need the build sheet. If it has been restored and there's no build sheet it's unlikely you'll find one. In fact I think the Lansing cars are known to rarely have had them anyway. Is there any other docs they have such as the sales invoice? That would tell you.
Thanks for the eBay link - not sure how I missed that as I had been looking there also. They are much more definitive about the "numbers matching" and having "original documentation" on eBay than on their web site (don't mention the build sheet). I asked the place for a clearer picture of the tag that was in one of the photos but not readable. Again not sure if that helps either way but it is attached - it looks like a COWL tag and the parts I can decipher seem correct at least in terms of 71 Cutlass Supreme Convertible manufactured in Lansing Michigan.
Paul, this car is also listed on eBay, and the listing states it is a numbers matching car. Again, absent a build sheet showing the Y79 option I'm not aware of another way to confirm it's definitely an SX. But numbers matching is good news. Here's a link to the eBay ad:
Paul, just FYI there are a couple things in the description that aren't factual. One states the '71 came w/either a 2BBL or 4BBL 455. The '71 only came with the L32 4BBL (the '70 models came w/various engine options that did include 2 and 4BBL options). Second, the SX decal on the dash/glove box is added aftermarket and did not come on the SX model. That could be something the prior owner liked and doesn't necessarily mean it's not a true SX.

This one seems to have all the hallmarks of a true SX, but absent the build sheet I'd want to know if it is a numbers matching car. That would be a very good indicator along w/the dual cutout exhaust and proper emblem locations on the fenders.

Good luck. I hope it is a true SX, it's a beautiful car.
This is my first time purchasing a classic car. I really like the 70/71 SX Convertibles. I found one that looks really nice at the link below. The VIN seems to be correct for a 71 Cutlass Supreme as well as the placement of the SX badges, 442 styled bumper, and exhaust cutouts. I also found that it was sold at a Barrett Jackson Auction in 2010 with consistent description/specs - doesn't look like much was done to it since then except it added about 30K miles. Any other thoughts on whether this one is/isn't a real SX?

Thanks for any input.

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